Donald Trump did not amass a majority of delegates on Super Tuesday. But he could soon.

If the people in the rest of the nation vote as the Super Tuesday results suggest they would, Mr. Trump would easily amass a majority of delegates and avoid the contested convention that his opponents hope to force and win.

He could even do so without wins in Ohio and Florida, the two largest winner-take-all states, where he faces opponents in their home states.

Mr. Trump would amass so many delegates because the rules become more biased toward candidates who win, allowing him the chance to take an overwhelming share of delegates with just a minority of the vote. It becomes easy to win lopsided delegate margins starting March 15, when states are allowed to apportion their delegates on a winner-take-all basis. At the same time, the primary calendar doesn’t become less favorable and may even become more advantageous to him, depending on which candidates stay in the race.

But the results so far also indicate he could still be defeated, suggesting Mr. Trump is far from winning a majority of the popular vote. He could be denied a majority of delegates if the field narrowed to Mr. Rubio.

If the remaining states vote as one would expect based on their demographics and the results so far, Mr. Trump will defeat Marco Rubio by a margin of 37 percent to 25 percent over the rest of the race. Ted Cruz would take third place over the rest of the primary season, with 22 percent of the vote. (These figures were calculated by weighting the candidate’s projected vote share in congressional districts by Mitt Romney’s vote in 2012, to more appropriately reflect the importance of caucuses. The actual popular vote would be worse for Mr. Cruz.)

Mr. Trump’s 12-point lead over Mr. Rubio would translate into a huge majority of the outstanding delegates. He would be favored to amass around two-thirds of the delegates that remain — or around 1,100 additional delegates on top of the more than 300 delegates he already holds. That would easily be enough for Mr. Trump to clear the 1,237 delegates needed to win.

It would even be enough to withstand losses in both Ohio and Florida, two big winner-take-all states.

It’s important to emphasize that these estimates aren’t predictions. They assume the rest of the country will vote as it has so far, and the race could easily change. Perhaps Mr. Rubio will fade after his showing on Super Tuesday. Maybe an organized “stop Trump” effort will have an effect.

But the estimates nonetheless make an important point: There won’t be a contested convention if things keep going as they have been.

Mr. Trump would fare well in the pure winner-take-all states as well as the states with a mix of winner-take-all by statewide vote and congressional district. Many of these states, like New York and New Jersey, are traditionally strong for establishment-backed candidates. But the results so far suggest Mr. Trump would have a significant advantage there, as he did in Massachusetts — his best state on Super Tuesday.

Mr. Trump is vulnerable in some states and at a disadvantage in few. He trails in just Kansas, Hawaii, North Dakota, Utah, Wyoming, Nebraska, South Dakota and Idaho. Elsewhere, Mr. Trump holds a lead and often a commanding one.

That doesn’t mean that his rivals can’t or won’t deny a majority of delegates to Mr. Trump.

It would be easier if Mr. Rubio, not Mr. Cruz, were the main rival to Mr. Trump. The model shows Mr. Rubio is on track to surpass Mr. Cruz in delegates by the end of the primary season, despite his struggles so far.

That may seem surprising, since Mr. Rubio has won fewer states than Mr. Cruz. But the states about to vote are more moderate and plainly worse for Mr. Cruz than the states that have already voted.

Mr. Cruz has nearly no chance to win the delegate-rich blue states later in the calendar. He’s not even on track to exceed 15 percent of the vote in several states where Mr. Trump would need to be slowed, while Mr. Rubio is in striking distance.

Mr. Rubio would need to beat Mr. Trump in several big winner-take-all or winner-take-most states.

In these projections, Mr. Trump amasses a huge 856-56 delegate lead over Mr. Rubio from the following 16 states: Arizona, Florida, Delaware, Indiana, Montana, New Jersey, Ohio, West Virginia, Pennsylvania, Illinois, Missouri, California, Maryland, New York, Wisconsin and Connecticut.

That huge delegate edge might seem to imply that Mr. Trump is really winning big, but many of these contests are relatively close — Mr. Trump just benefits from the growing “winner bias” of the Republican delegate rules. Mr. Rubio would not need to make too many gains to deny Mr. Trump a majority.

Mr. Trump would need to lose about 200 delegates from these states. Florida and Ohio, worth about 165 delegates, would cover much but not all of the distance. Realistically, though, stopping Mr. Trump at the convention might require holding him more comfortably beneath the 1,237 needed to win.

What would that look like? Just add the Kasich vote to Mr. Rubio’s. That’s not quite how it would work in the real world — Mr. Rubio wouldn’t win 100 percent of the Kasich vote if he dropped out — but it’s useful for illustrative purposes.

Adding the Kasich vote gives Mr. Rubio additional wins in Wisconsin, Washington, New Mexico, California, South Dakota, Arizona, Oregon, Maine, Maryland and Nebraska. If you give Mr. Rubio and Mr. Kasich the same home-state advantage that helped Mr. Cruz win in Texas, then they win Ohio and Florida (although polls do not show Mr. Rubio with such an edge in Florida). It would cut deep into Mr. Trump’s delegate edge in states like New York and Illinois.

In the end, the Republican rules aren’t very complicated. If Trump can win by the margin he did on Super Tuesday, he’s going to earn a majority of delegates no matter how many candidates remain in the race. If another candidate, most obviously Mr. Rubio, can start to fight him to a draw in the later states, then Mr. Trump could be denied a majority of delegates. The results so far suggest that’s possible, since Mr. Trump is not close to the pace needed to win a majority of the popular vote.

Whether Mr. Trump would lose the nomination if he entered the convention with a large plurality of delegates is a separate question. But a contested convention is nonetheless the best the traditional candidates can hope for.